ML20237L271
| ML20237L271 | |
| Person / Time | |
|---|---|
| Issue date: | 08/24/1987 |
| From: | Novak T NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Rossi C Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20237L250 | List: |
| References | |
| NUDOCS 8708280032 | |
| Download: ML20237L271 (2) | |
Text
_ - - _ - _ --
a
- i D 8 4 1937 ;
i MEMORANDUM FOR: Charles E. Rossi, Director [
Division of Operational Events Assessment 1 Office of Nuclear Reactor Regulation FROM: Thomas M. Novak, Director l Division of Safety Programs 1 Office for Analysis and Evaluation of Operational Data j
SUBJECT:
AUXILIARY FEEDWATER PUMP TRIPS CAUSED BY LOW i SUCTION PRESSURE l Enclosed is an Engineering Evaluation Report on the above subject recently I completed by this office. Our review indicates that the low suction pressure trips of the AFW pumps were attributed to pressure oscillations or fluctuations j in the suction lines, which created a momentary pressure drop despite j sufficient available suction heads. The momentary low pressure was sensed and <
i actuated the pressure trips of the pumps. The operational conditions which contributed to the occurrence of pressure oscillations or fluctuations, appear i not to have been fully specified or considered in the design of the pump low . ,
suction pressure protection systems.
The events show that low suction pressure trips constitute a common-mode failure that can potentially render the AFW system inoperable and the plant would loose its redundancy in core heat removal capability. Although the trips may be removed in a relatively short period and the pump restarted, the potential exists that system response time may exceed the time limit required by the plant Technical Specifications, and the reliability and capability of the AFW system could be compromised.
In view of this safety concern, it is suggested that NRR issue an information notice to inform licensees of the ootential for loss of AFW capability due to spurious low suction pressure trip signals. A draft of the proposed information notice is attached for your consideration.
8708200032 870824 PDR ORO NEXD PDR
_m - ___.__ _ _ _ . _ _ _ _
a, -
Charles E. Rossi If you have Chuck ouestions Hsu (x24443) of or mycomments, staff. please do not hesitate to contact me or staff to discuss this matter. We shall be happy to meet with you or your Original Signed By Jhomas M. Novak Thomas M. Novak, Director Division of Safety Programs Office for Analysis and Evaluation of Operational Data
Enclosures:
As stated cc w/ enclosures:
E. Jordan C. Heltemes
\
_ DISTRIBUTION:
'tPDR;.
ROAB RF CHsu MChiramal JRosenthal MWilliams KBlack VCenaroya THovak JJohnson 0FC : ROAB:DSP : R OAB:DSR : ROAB:DSPA :'
_____:_______.k.e_:. ______1ct.:.________4.91:._ :0SP : DD:DSP : :
NAME : CHsu:as : MChiramal : JRosenthal VBe, oya :
DATE : 8/f/87 : 8/J'/87 : 8/4 /87 ; / /87
- 8//'787 : :
0FFICIAL RECORD UOPY /'
_ . . .